Full list of all 23 Destiny 2 achievements worth 1,240 gamerscore. It takes around 80-100 hours to unlock all of the achievements in the base game on Xbox One.
The base game contains 13 achievements worth 1,000 Gamerscore, and there is 1 DLC pack containing 10 achievements worth 240 Gamerscore.
Complete a Nightfall strike on Grandmaster difficulty.
Encounter an Agent of the Nine somewhere in the system.
Complete the "Light Reforged" quest.
Acquire each Titan subclass.
Collect 15 Red War exotic weapons or armor.
Complete a Nightfall strike.
Complete 30 challenges.
Complete 5 Heroic Public Events.
Acquire each Hunter subclass.
Complete a Nightfall strike on Master difficulty.
Acquire each Warlock subclass.
Reach level 20.
Complete a Heroic public event.
Collect 10 Forsaken Exotic weapons or armor.
Defeat a Forsaken Nightfall Boss.
Collect 15 Forsaken Exotic weapons or pieces of armor.
Win a Gambit match.
Enter the Dreaming City.
Complete the "Shattered Throne" dungeon.
Earn 5,000 Triumph points.
Complete a Collections Badge.
Complete a Triumph Seal.
Complete the "Last Wish" Raid.